Inhibiting precipitation in malt beverages



United; States ate '7 Claims. (61. 99:- -4.8)

iNHrBITING I flf his invention relates to an improved process forinhibiting the formation of calcium oxalate in malt beverages, and forthe prevention of hazes and sediments due to" said calcium oxalate.Improved physical characteristics and an increased aesthetic appeal arefurther im-. provements that result from the invention.

Malt beverages such as beers and tributed in packaged form, that is, inglass bottles and tin cans. This packaging and wide distribution of thebeverage makes it necessary to have a beverage able to withstand theadverse conditions of both higli'and' low temperatures, vibration,exposure to light, traces of certain metals and anions, and otherfactors that aifect its stability and shelf-life. The beverage mustreach the consumer in a brilliant condition with unchanged flavor andthe ability to remain clear and free of sediments when subjected tovariable storage conditions and to chilling before consumption.

Briefly, the brewing process comprises the treatment of an aqueoussuspension of malt and other starchy materials under certain definitetemperature conditions to partially convert the aqueous starchsuspension into a solution of fermentable sugars. This solution isfiltered off from the husks and other insoluble matter of the malt. Thesugary solution is boiled with hops and then cooled. The cooled liquoris treated with yeast and subjected to a slow low-temperaturefermentation. The fermented liquor after partial clarification bysettling and removal of the yeast is stored cold and treated withchillproofing enzymes. During this and further processing, the beer maybe subjected to one or more filtrations to produce a sparkinglybrilliant liquid. This highly clarified, sparklingly clear beer is thenpackaged and the package is usually subjected to pasteurization beforedistribution to the consumer. Emphasis is placed on the production of abeverage that is sparklingly clear because the present day consumerdemands this type of beverage. Beverages which are not perfectlybrilliant and clear or which contain even slight traces of haze orsediments are unacceptable to the consumer.

The use of chillproofing enzymes during the beer processing is a stepcommonly employed to prevent the formation of certain types of proteinhazes due to the insolubility of various high molecular weight proteincomplexes at low temperatures.

There are other types of haze formations which can develop in beerbesides the protein type of chillhaze. Such types are not amenable tothe treatment by proteolytic enzymes. One such type is a haze orsedimentation formed by the gradual precipitation of calcium oxalate.This invention is specifically concerned with the inhibition of theformation of calcium oxalate microcrystals and hazes.

During the preparation of the beer oxalic acid may enter the liquorsduring mashing since oxalic acid is a normal trace constituent of themalt. The use of hops during kettle boiling may introduce additionalquantities. It is possible that further traces may be formed as a lesare widely disforming undesirable hazes.

Patente Sept,v 2.3, 195.9.

result of the metabolism of the yeast during fermenta? tion. Sincecalcium ion is-also always present in relatively considerable amounts,generally the. bulk of the oxalic acid is precipitated as the insolublecalcium oxalate duringfermentation and is separated from the beer alongwith the settled yeast. Inasmuch as calcium oxalatehas a slightsolubility in beer and theprecipitation of calcium oxalate at this pointmay be incomplete, variable amounts of the oxalate ion may be left insolution depending upon certain conditions incident to. the particularbrew. This soluble oxalic acid will then be carried through into. thefinished beverage and may serve as a possible source of furtherprecipitation. Whether or not such precipitation can occur in thefinished packaged beverage. is dependent not only on the conditionsunderwhich the package is subsequently handled and held in the trade buton such processing factors prior to packaging as cellar storageconditions and duration, calcium as well as oxalate levels, and stage atwhich both calcium and oxalate may; have entered the product. t

The finished beverage after packaging is subjected: to a wide variety ofstorage conditions and time periods before consumption; This soluble.oxalic' acid may then react with the calcium ions-normally present inbeer and fur ther precipitate small amounts'of: calcium oxalate, Onfurther standing these crystals will tend to grow forming increasingturbidities and unsightly sediments in the beer. Beers suffering fromthis continued precipitation of calcium oxalate are unacceptable to theconsumer. Where calcium oxalate sediments are formed in the finishedpackaged beverage they may take a wide variety of crystalline forms.Some investigators believe under certain conditions there may be aconnection between oxalate separation and the phenomenon of wild orgushing beer.

The amounts of oxalic acid which may occur in beer after precipitationof the calcium oxalate during fermentation are only at trace levels ofthe order of possibly 10 p.p.m. or less. However, these traces areenough to produce effects on the clarity of the beverage and form hazeand sediment out of proportion to the actual amounts involved.

We have found that the treatment described below effectively inhibitsthe formation of the microcrystalline calcium oxalate hazes andsediments. This treatment comprises the addition to the beer, afterfermentation and preferably after an initial clarification, of a smallamount of a soluble amidopolyphosphate, such as may be obtained by thereaction of ammonia and phosphorus pentoxide. The amount ofamidopolyphosphate required to accomplish the objective of preventingprecipitation of microcrystalline calcium oxalate is very small. For theamounts of oxalic acid occurring in beer which normally may causetrouble, levels of only 10 p.p.m. or less of the solubleamidopolyphosphate are required. A preferred range is in theneighborhood of 5 p.p.m. inasmuch as excessive amounts of theamidopolyphosphate tend to produce hazes in beer on their own account.

An amidopolyphosphate which has been found suitable is the productformed by reacting anhydrous ammonia with phosphorus pentoxide attemperatures of above C. to produce a complexnitrogen-phosphorusoxygen-containing material having possibly a cyclicstructure. Methods for the preparation of these materials are describedin U.S. Patent No. 2,122,122, issued to Willard H. Woodstock. Productsof this type are available commercially and may be obtained from VictorChemical Company, Chicago, Illinois, under the name Victamide, which isthe trade name for an ammonium salt of an amidopolyphosphate.

The addition of this small amount of an amidopolyphosphate effectivelyinhibits the crystallization of the calcium oxalate and prevents hazeformation or precipitation from this source. The amidopolyphosphate maybe added any time after fermentation but is preferably added while thebeer is being transferred from the fermenter to the storage tanks orjust after the first filtration prior to the final polishing filtration.A convenient mode of addition is to prepare a concentrated solution ofthe material in water and pump it into the beer through a proportioningdevice while the beer is being moved during processing.

Thus, by way of example, the amidopolyphosphate composition of US.Patent No. 2,122,122 may be added to beer in the amount of about 5 partsper million by adding a concentrated solution of the amidopolyphosphatein water to the beer by means of a proportioning device as it is beingtransferred to the final polishing filtration.

The addition of the soluble amidopolyphosphate to the beer at thesetrace levels has no eifect on the taste or color of the beer, nor anyadverse action on the chillproofing enzymes. The use of this materialdoes not require any other change in the normal processing of the beeras now customarily conducted.

This application is a continuation of our application Serial No.587,446, filed May 28, 1956, now abandoned.

We claim:

1. Process of inhibiting the precipitation of calcium salts in maltbeverages containing the same which comprises the addition of anamidopolyphosphate to the malt beverage.

2. Process of inhibiting the precipitation of calcium oxalate in maltbeverages which comprises the addition of an amidopolyphosphate to themalt beverage.

3. Process of inhibiting the precipitation of calcium oxalate in maltbeverages which comprises the addition of an amidopolyphosphate inamounts of up to about 10 parts per million to the malt beverage.

4. Process of inhibiting the precipitation of calcium oxalate in maltbeverages which comprises the addition of an amidopolyphosphate obtainedby reacting anhydrous ammonia with phosphorus pentoxide at a temperatureabove C. to the malt beverage.

5. Process of inhibiting the precipitation of calcium oxalate in maltbeverages which comprises the addition of an amidopolyphosphate obtainedby reacting anhydrous ammonia with phosphorus pentoxide at a temperatureabove 150 C. in amounts of up to about 10 parts per million to the maltbeverage.

6. A malt beverage containing an amidopolyphosphate in an amounteffective to inhibit the formation of calcium oxalate hazes.

7. A malt beverage containing an amidopolyphosphate in amounts of up toabout 10 parts per million effective to inhibit the formation of calciumoxalate hazes.

References Cited in the file of this patent UNITED STATES PATENTS2,122,122 Woodstock June 28, 1938

6. A MALT BEVERAGE CONTAINING AN AMIDOPOLYPHOSPHATE IN AN AMOUNTEFFECTIVE TO INHIBIT THE FORMATION OF CALCIUM OXALATE HAZES.